Art of cracking hydrocarbons



Sept. 2, 1930. E. w. ISOM ET: AL 1,774,602

ART OF CRACKING HYDROGARBONS Filed July 12, 1929 INVE TORS fdwaro/l l 50m ig are (T b rf/ie/ GWWML ATTORNEYS Patented Sept. 2, 1930 UNITED, STATES-"PATENT OFFICE EDWARD W. ISOM, F SGARSIDALE, YORK, AND EUGENE C. HERTHEL, OF CHICAGO, ILLINOIS, ASSIGNOIRS T0 SINCLAIR REFINTNG COMPANY, OF NEW YORK, N. Y., A

conronnrrron or MAINE ART OF CRACKING HYDROCAR BONS Application filed m 12,

This invention relates to improvements in the manufacture of lower boiling hydrocarbon oils, such as gasoline, from higher boiling hydrocarbon oils, such asgas oil. The

' invention will be described in connection with the accompanying drawings which illustrate,

diagrammatically and conventionally, appa-- ratus embodying and for carrying out the invention. In the accompanying drawings, Fig. 1 represents, in elevation and partly in section and with parts broken away, apparatus embodyingand adapted for carrylng out the invention and Fig. 2 is a fragmentary section through and just above the lower ends of the heating tubes illustrated in Fig. 1.

Referring to the drawings, a stream of high boiling oil is forced, by means of pump 2, through a battery of series connected banks ofserles connected vertical heating tubes ar-. ranged 111 a'heatlng flue in heating furnace 1 into the vapor separating receptacle 3 from which vapors including vapors of the desired low boiling oil are taken off, the oil-be-' ing heated to a cracking temperature during passage through the heating tubes. The battery of heating tubes consists, as just 'mentioned, of a plurality of series connected banks 11, 12, 13, 14,15,16, 17 and 18 of heating tubes each of which banks consistsof a plurality of series connected heating tubes. These several banks of heating tubes are arranged transversely to the general direction a of flow of the heating gases through the heating flue. The heating gases enter the upper end of the heating flue through passage 4 from the firebox 5 in which fuel is burned for supplying heat to the operation and pass in alternating down and up and down flow through the heating flue to the stack flue 6. The oil flowing through the series connected banks of heating tubes flows successively upwardly and downwardly, in alternating flow,

through the series connected heating Itubes forming the several banks. The alternations in flow of the heating gasesare substantially less in numberthan the alternations in fiow of the stream of oil flowing through the banks;

of heating tubes; that is theoil flow alter.

nates several times between eachalternation in flow of the heating gases. I Theoil supthrough 1929. serial in 377,815.

plied to the battery of heating tubes, through connections 7, flows first through bank 18, then through bank 17, then through bank 16 andso on, until discharged from bank 11 through connection 8. The flow ofheating gases through the heating flue in which the heating tubes'are arranged is directed,' as just described, by means of the baffles 9 and 10.

The vapors taken oif from the vapor separating receptacle 3, through connection 19,

are subjected to a refluxin operation in reflux tower 20 from which thevapors remaining uncondense'd escape through connection 21 to the condenser 22 arranged to discharge into the receiver 23 from which a condensed distillate product is dischargedthrough connection 24 and uncondensed vapors and gases through connection 25. Pressure in the vapor separating receptacle 3 may be maintained and regulated by means of valve 26, or by means 'of suitable valves arranged beyond the condenser. or receiver. Raw oil is supplied to the refluxing operation through connection 27 by means of pump 28, and utilized therein as a direct refluxing medium for 1 effecting-and controlling the operation. Ad mixed reflux condensate and raw oil are supplied to the battery of heating tubes arranged in the heating furnace 1 from the refluxing operation through connections 29, 30 and .8

by means of'pump '2. Residual oil is discharged from the vapor separating receptacle 3 throu h connection 31;

"In initiating operation, 011 is circulated i from the vapor separating receptacle 3, by means of valved connection 32, through the battery of heating tubes and back. to the tional raw oil, in addition to that supplied connections 32, 30 and 34. Addi through connection 27, may be supplied through connection 34 duringoperation. In carrying out the invention in the apparatus illustrated, vapors may be taken ofi' from the vapor separating receptacle 3 under a pressure in the general range of 100-300 pounds per square inch, for exam le, and the oil forced through the battery 0 heating tubes may be heated therein to a temperature approximating 825-875 F. as discharged through connection 8 into the vapor separating receptacle 3, for example. The rate at which raw oil is supplied through connection 27 may be regulated to condense in the refluxing operation all constituents higher boiling than suitable as components of the desired distillate product, and residual oil may be discharged through connection 31 at a rate regulated to maintain a uniform liquid level in the vapor separating receptacle 3.

Instead of taking 01f vapors from the vapor separating receptacle 3 under substantial superatmospherie pressure, vapors may be taken off from the-vapor separating receptacle?) under a pressure in the generalrange of 1-10 pounds per square inch or under a somewhat higher pressure, for example, and the oil forced through the battery of heating tubesmay be heated therein to-a temperature approximating 850-925 F, as discharged therefrom, under a pressure in the general range of 300-600 pounds per squareinch, for example, this pressure being regulated and releasedby means of the valve 35.

In the apparatus illustrated, the vapor separating receptacle 3, the reflux tower 20, and connections 8, 19.29, 30 and 7 are with advantage thoroughly lagged orthermally in-' sulated.

The heating furnacel may, with advantage, bearranged and operated as described in Letters Fatent Nos. 1.574.546 and 1,574.54-7,

issued to Sinclair Refining Company, February 23, 1926, on application of the late John E. Bell 'or as described in Letters Patent No. 1,623,773, issued to Sinclair Refining Company, April 5, 1927, on application of the late John E. Bell. 7

While the invention has been described more particularly as applied in conjunction with pressure distillation, or so-called pressure shell. cracking operations, in connection with which it is of special value, it is i also useful as applied in conjunction with operations in-which high boiling oil is heated to a cracking temperature under high pressure and in which the hot oil products of this heating operation are separated into a vaporized fraction and an unvaporized vfraction under lower pressure, or so-called pressure coil cracklng operatlons. r

We claim: In the manufacture of lower boiling hydrocarbon 0115 from higher bolllng hydrocarbon 011s the lmprovement whlchcomprlses forcing a stream'of high boilin oil through a battery of series-connected anks of series connected vertical heatingtubes arranged in a heating flue into a vapor separating receptacle, passing heating gases from a firebox in which fuel is burned for supplying heat to the operation in alternating down and up flow through said heating flue in a direction generally transverse to said banks of heating tubes, these alternations in flow of the heating gases being however substantially less in number than the alternations in flow of the stream of oil flowing through said series-conneeted banks of series-connected heating tubes, thereby heating the oil to a cracking temperature, and taking off vapors including vapors of the desired low boiling oil from said vapor separating receptacle.

In testimony whereof we afiix our signatures.

EDWARD .W. ISOM. EUGENE C. HERTHEL. 

